When buckling a seat belt, a user inserts a male tongue with an opening at its leading end into a female buckle assembly. The buckle assembly generally includes a latch opening, a spring-loaded latch plate, and a locking mechanism. When the user inserts the leading end of the male tongue into the buckle assembly, a portion of the latch plate is designed to pass through the tongue opening and into the latch opening, resulting in the male tongue being locked in place in the female buckle by the locking mechanism. The latch plate successfully inserted through the tongue opening and into the latch opening such that the locking mechanism is fully engaged in the properly latched, fully locked position is referred to herein as the “locked position.” To unbuckle the seat belt, the user typically pushes on a release mechanism (e.g., button) on the buckle assembly to disengage the locking mechanism such that the tongue is able to be freely removed from the buckle assembly. The release mechanism being activated so that the locking mechanism is disengaged is referred to herein as the “unlocked position.”
One example of this type of seat belt design is exemplified in U.S. Pat. No. 6,233,794, the disclosure of which is incorporated herein by reference. As shown and described in the '794 Patent, its buckle assembly generally includes a frame having lower and upper frame portions, a latch plate that is linearly translatable within the frame, and a tongue having a tongue opening. The lower frame portion includes a latch opening and two raised sides extending substantially perpendicular to opposing sides of the latch opening. The raised sides include slots disposed therein to allow for linear translation of the latch plate. The first frame portion and second frame portion are able to be assembled together to form a slot for receiving the tongue. In operation, the tongue is inserted into the slot of the assembled frame and the latch plate is biased towards the lower portion of the raised sides of the lower frame portion such that the middle latch portion of the latch plate traverses the tongue opening and is inserted into the latch opening.
“False latching” is a not uncommon seat belt malfunction which occurs when the seat belt tongue is believed by the user to be in the locked position when in fact the latch has not successfully been completely inserted through the tongue opening. As a result, the locking mechanism is not fully engaged and the seat belt buckle is not in a safe position. False latching occurs because the latch plate stays in the buckle and looks, feels, and/or sounds like it is secured in the locked position to the user by virtue of the fact that part of the latch plate has been inserted through the tongue opening and partially into the latch opening. However, because the locking mechanism is not fully engaged, the male tongue may be withdrawn from the buckle assembly as a result of an automobile crash, the loading of the seat belt by the occupant and/or contact directly with the seat belt buckle (hitting of the seat belt buckle). For purposes of the present disclosure, the latch plate being incompletely inserted through the tongue opening without the release mechanism being activated is referred to herein as the “false latched position” (also known as a “false locked position”).
What is needed therefore is a seat belt buckle design that eliminates false latching and significantly reduces the chance of partial engagement of the latch plate with the latch opening.